The present invention relates to metal, working, and more particularly to machines for spinning of tubular workpieces.
The proposed invention may be suitably used in the production of hollow axisymmetric articles from tubular workpieces, for example, in the production of cylinders from pipes of undefined length, which are cut off concurrently with spinning of the bottom and neck portions thereof. This invention is also suited for obtaining various reductions at the end portions of pipes or elsewhere along the length thereof, as well as for reducing the end portions in articles constructed from pipes, such as high-pressure cylindrical vessels, deep-bottom cylinders, along with hollow hermetically sealed ends of spheres and semi-spheres, articles having a recurring profile, and complex-shaped bottoms.
Known in the prior art are machines for spinning of tubular workpieces, wherein a workpiece and a tool have parallel axes of rotation, comprising a bed with a spindle rotatably mounted thereupon and fitted with a device for clamping the workpiece, said spindle being made as a chuck. The workpiece is arranged in the spindle so that its end, the length of which is equal to that of the spinning zone, extends outside. Mounted on the bed ahead of the spindle is a feeding carriage having a cross feed with respect to the axis of rotation of the spindle with the workpiece. Fixed on the feeding carriage is a forming tool with a drive adapted to turn the tool. The tool is made as a roller having a configuration such that its successive sections make for smooth transitions from the initial shape of the workpiece generatrix to a desired shape thereof. The axis of the tool is parallel to the rotation axis of the spindle.
A pre-heated tubular workpiece is first fed into the rotating spindle, then centered and clamped in the chuck. Thereafter the forming tool rotation drive is actuated and the spinning process is carried on by way of continuous sliding friction of the workpiece against the forming tool.
The disadvantage of the aforesaid machine lies in the fact that it is capable of carrying out spinning only of the end portion of a tubular workpiece, and also that said workpiece is necessarily subjected to rotation in a machine, which is undesirable in the case of long-length tubes.
There is also known a machine with a tangentially fed forming tool, adapted for hot spinning of spherical bearings and flat bottoms of telescopic hydraulic jacks used in tipping trucks.
The above machine comprises the following units: a bed; a spindle mounted on said bed in bearing assemblies; a spindle drive mounted within said bed; a feeding carriage arranged on the bed ahead of the spindle and provided with a hydraulic drive accommodated within said bed.
The spindle is fitted at its end with a jaw chuck collet which is tightened by means of a V-ring. Arranged within the spindle is a positive stop with a feed spring.
The upper part of the feeding carriage mounts a table moving in transverse direction with respect to the spindle. Affixed on the table is a forming tool.
A pre-heated workpiece is fed into the spindle as far as it can go, causing the spring to contract. The workpiece is clamped in the chuck collet which is set in rotation. The hydraulic cylinder is then actuated to provide for the cross feed of the forming tool having such a configuration that its generatrices allow, in the course of spinning, for successive transitions from the initial shape of the workpiece to a desired shape thereof. With the spinning process being over, the chuck collet is opened, the compressed spring is released and the workpiece is pushed out of the spindle.
The disadvantage of said machine lies in the fact that it allows spinning only of the end portions of tubular workpieces. The spindle interior limits the length of a workpiece to be worked, while imperative rotation of the workpiece in the spindle is undesirable in case of long-length tubes.
There is also known a machine for the spinning of tubular workpieces, in which the working process is realized by means of a tangentially moving forming friction tool, with the furnished tapered portion of the workpiece being cut off.
The aforesaid machine comprises a bed which mounts a driven hollow spindle fitted with a chuck for clamping a workpiece. Mounted on the bed ahead of the spindle is a cross slide on which are affixed a forming tool and a cutter adapted for cutting off the worked piece. The cross slide is driven by means of a motor through a program drum tracer which allows for the slide to travel forward at a greater speed during spinning operation and at a lower speed during cutting-off operation, with subsequent retreating of the slide to its initial position. The drive mechanism of said slide is mounted on the machine bed.
A pre-heated workpiece is thrust into the spindle to be clamped in the jaw chuck. The spindle is then set into rotation by means of the motor through a belt drive. In the course of the interaction between the rotating workpiece and the transversely moving forming tool, the heated end of the workpiece is caused to deform.
The spinning operation being over, the chuck jaws are unclamped and the workpiece is released from the spindle.
The disadvantage of the aforesaid machine resides in that spinning can be carried out only at the end portion of the workpiece, and also in that the workpiece has to be rotated which is undesirable in case of long tubes.
There is known still another machine for the spinning of tubular workpieces, comprising a bed on which a spindle is mounted in bearing assemblies wherein the spindle is provided with external and internal shafts. Said shafts are set into rotation by means of a motor through a belt drive and two gear drives having different speeds of rotation due to the difference in the value of the gear train thereof. The motor is located on the machine bed. Fitted on the spindle external shaft is a spindle nose with a faceplate, and arranged in said spindle nose are axles with a forming roller and an anvil roller mounted thereon. Fitted on the free ends of said roller axles are gear wheels internally toothed with gear cages mounted on axles which, in turn, are arranged on auxiliary axles arranged within the spindle nose. The gear cages are externally toothed with the gear wheel fitted on an internal shaft. The workpiece together with the clamping device is rigidly fixed foward of the spindle with the faceplate whereby the roll-forming of the workpiece free end is made possible.
To start the operation, the motor is energized to impart rotation to the spindle through the belt drive and gear drives. The forming tool is rotated about the axis of the workpiece. Due to a slight speed difference in rotation of the internal and external shafts, the rotation is imparted through the gear pair to the axle on which is mounted the tool.
The production potentialities of the hereinbefore described machine are limited in that it does not provide for the spinning of a tubular workpiece other than at the end portions thereof. It is likewise impossible to obtain several profiles in the workpiece at one time.